Frequent traveler Peter Juhren was so flustered by the controls of the Lincoln MKX rental car he picked up in September at the Calgary airport in Canada that he wanted to return the car almost as soon as he got it.

"By the time I reached the hotel, all I wanted to do was return the vehicle for a standard old run-of-the-mill Chevy Impala that I could at least control," says Juhren of Salem, Ore., who works in the tower crane sales and rental business.

Juhren is among many savvy travelers who complain about the confusion, frustration and time lost trying to figure out how to operate their rental vehicles.

Controls and functions vary among models and are often unlike their own cars. Reaching for the glove box can also be a futile exercise for renters because operating manuals are often missing.

Too many buttons

After getting inside the Lincoln he rented from National Car Rental in Calgary, Juhren says it took several minutes to figure out how to turn the radio off. It was "another search and destroy mission" to set the climate control, he says.

After driving for 15 minutes toward the hotel, he pulled over to figure out how to adjust the touch-screen lighting on the dashboard because it was very dim.

"By now," he says, "the inside of the car was 85 degrees, and it was all I could do to just turn off the climate control and forget it's only 2 degrees outside."

Juhren implores carmakers to simplify controls. He blames them, not National or other auto rental companies, for his frustration.

"They must offer a variety of vehicles and classes and are at the mercy of the manufacturers," he says. "It's not feasible for them to offer an orientation for each vehicle."

National's Emerald Club program for frequent renters is geared to "road warriors who typically are looking for the fastest way of getting through the airport and on the road as soon as possible," she says.

She says Enterprise Rent-A-Car's operations involve employee interaction during the selection of a vehicle, which provides more one-on-one time with customers to review vehicles overall.

Enterprise Holdings' car rental customers also can also use smartphones to scan QR codes, located on key tags, to launch an OnRamp Concierge site. She says it has information about features for most vehicles in the company's fleets, though it's not as detailed as owners manuals.

Enterprise Holdings' policy is to have an owners manual in the trunk of each car. But, she says, "Renters sometimes borrow them and forget to return them."

Hertz says it has an owners manual in every vehicle. Hertz spokeswoman Paula Rivera says the company "prides itself on ensuring its customer-service employees have the tools available to address any vehicle operating questions."

Hertz also has vehicle guides available to employees on its internal website to educate them, she says.

Avis Budget Group spokeswoman Alice Pereira declined to comment whether the two brands have owners manuals in cars. But in a written statement, Pereira says customer safety is very important.

"We strongly encourage renters to familiarize themselves with their vehicle before leaving the lot," she said. "This includes adjusting the seat and mirrors; knowing where and how to operate the headlights, windshield wipers, window controls, door locks, gas tank access and climate controls."

Avis and Budget agents will assist if customers have questions or can't figure out how to work any of the features, she says.

Dollar and Thrifty locations are staffed by agents "with knowledgeable employees who are available to explain unique keys and other functionality whenever possible," she says.

Dollar and Thrifty try to ensure employees are kept up to date about their fleet's various options and educate them before bringing in new vehicles, Bootenhoff says.

"There there is no time limit on how long a customer may sit in the car before deciding to leave," she says. "Customers are encouraged to take as much time as needed before driving off to become familiar with the vehicle."

Besides counter agents, Dollar and Thrifty employees are available to assist at many rental lots and all exit booths, she says. Renters can also call roadside assistance or customer service agents.

X marks the spot

Frequent traveler Steve Miller, a professional speaker who lives in Federal Way, Wash., needed assistance after renting a Ford Fusion from National at the Phoenix airport in April.

Miller says he asked his wife, Kay, to turn on the air conditioning while he inspected the outside of the car. When he got inside, he says, "the air is going full blast, but now the hazard lights are blinking. Somehow my wife turned them on accidentally."

They looked for the hazard button for about 15 minutes, he says. The car had a manual, but it only said the button was on the instrument panel, and they still couldn't find it.

"We finally asked one of the National employees to help," Miller says. "He couldn't find it either, until he turned his flashlight on. The button was located high up on the panel in between two air vents. Even he was surprised how hard it was to find."